Seriously Skeletal System

System Anatomy Bones – 206 (axial and appendicular) Joints - articulations Cartilage – connective tissue Ligaments – connect bone to bone

System Physiology Support body and form internal framework Protect soft body organs (i.e. skull) Movement – skeletal muscles use bones as levers to move body Storage – fat, minerals (calcium/phosphorus) Blood Cell Formation – happens in marrow of certain bones

Bone Classification Long Bones – longer than they are wide –i.e. humerus, femur

Bone Classification Short Bones – cube shaped containing spongy bone –i.e. bones of wrists and ankles

Bone Classification Flat Bones – thin, flattened and usually curved –Skull, ribs, sternum

Bone Classification Irregular Bones – bones that don’t fit in any other category –i.e. vertebrae, hip bones

Bone Markings Projections – sites of muscle, tendon and ligament attachment Depressions – sites that allow blood vessels and nerves to pass; can be articular surface

Projections/Processes (bumps) Tuberosity: large rounded projection Crest: Narrow ridge of bone Spine: Sharp, slender, pointed projection

Depressions/Cavities Meatus: Canal-like passageway Fossa: Shallow depression in a bone Foramen: Round or oval opening through bone

Long Bone Epiphysis – end of long bones, filled with spongy tissue. Diaphysis (shaft) – makes up most of the bones length, composed of compact bone. Periosteum – fibrous connective tissue membrane. It protects the diaphysis. Cartilage – prevents friction between bones Spongy bone – small needle-like pieces of bone and lots of openings.

Marrow –Yellow marrow – adult – stores fat –Red marrow – infant – makes blood cells Compact bone – dense and looks smooth and homogeneous. Medullary Cavity – storage area for fat

Microscopic Bone Anatomy Osteocyte: mature bone cell Lacunae: tiny cavity surrounding bone cell Lamellae: concentric circles Canaliculi: tiny canals that transport nutrients to each bone cell

Microscopic anatomy (cont.) Central Haversian Canal: carries blood vessels and nerves to all areas of bone Osteon: Canal + Matrix rings (the whole thing)

Articulations   Where bones meet   All bones meet with at least one other bone except the hyoid bone, which holds your tongue in place.

Types of Articulations A. Synarthrosis Structural- what is made out of? –Fibrous tissue Functional- What does it do? Bones are immovable for best protection Example - skull sutures (stitches) that hold the skull bones together.

Articulations Continued B. Amphiarthrosis Structural (what it is made out of.) –Cartilaginous (cartilage) Functional Holds bones together, But they are slightly movable Example: vertebrae to vertebrae

Classification of Articulations C. Diarthrosis Structural Filled with Synovial fluid (fluid-cavity) –Function: Makes a freely movable joint. -Examples - ball and socket and hinge joints of hip, shoulder, elbow